Weir screens for refrigerators

ABSTRACT

A refrigerator with a refrigerated interior space can have an air curtain separating air in the refrigerated interior space from air exterior to refrigerator. The air curtain can be established by a fan that blows air though an air outlet towards a corresponding air inlet that recovers air from the air curtain for recirculation to the air outlet. A first weir screen can be positioned proximal to the exterior space and a second weir screen can be positioned distal to the exterior space. A channel can be formed between the first weir screen and the second weir screen for receiving air from the air curtain before it is recovered by the air inlet.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent Application No. PCT/GB2021/050157, filed Jan. 22, 2021, entitled “Improvements to Open Display Refrigerators,” the entire contents of which are hereby incorporated by reference. International Patent Application No. PCT/GB2021/050157 claims priority to UK Patent Application No. 2001071.6, filed Jan. 24, 2020 and entitled “Improvements to Open Display Refrigerators.”

FIELD

The invention relates to improvements in open display refrigerators.

BACKGROUND

Open display refrigerators are commonly used in retail environments, such as supermarkets and grocery stores. An open display refrigerator allows customers to view and readily access chilled goods that are stored within the refrigerator.

This type of refrigerator has an air curtain, which is established by blowing cold air across the front of the refrigerator. The air curtain issues from an air outlet at the top of the refrigerator towards an air inlet at the bottom of the refrigerator. The air inlet recovers air from the air curtain and recirculates it to the air outlet via a cooling heat exchanger and fan.

The air curtain prevents cold air in the refrigerator from mixing with warm air exterior to the refrigerator. However, it is rather inefficient, in particular because the air curtain tends to spill out from the bottom of the refrigerator and warm air from the exterior becomes entrained into the air curtain. To overcome this problem, open display refrigerators often use a weir screen (also known as a riser), located on the base deck of the refrigerator and in front of the air inlet, to prevent the air curtain from spilling out from the bottom of the refrigerator. Typically, under the base deck of the refrigerator are a bank of fans for sucking the air curtain into the air inlet and a heat exchanger for cooling the air recovered via the air inlet. The fans also push the cooled air through the cavities of the refrigerator, to create a constant recirculation for cooling the refrigerator.

Typically, the suction pressure that the fans apply to the air inlet is limited and some air is lost over the edge of the weir screen where the fans are unable to suck it into the air inlet. Additionally, at the base of the refrigerator, the air curtain is at its warmest and at its most fragmented. This warmer air impacts items, such as food products, at the front of the base shelf, causing the items to be warmer than required. Further, in refrigerators where the rear wall is perforated, some air is pushed through the perforations to create a horizontal, cross-draft of cold air across the shelves; however, at the base of the refrigerator, this cold air is typically not sufficient to mitigate the warming caused by the air curtain.

It would therefore be desirable to provide an open display refrigerator, with a weir screen for preventing the air curtain from spilling out from the bottom of the refrigerator, which reduces the impact of relatively warm air from the air curtain on items at the base of the refrigerator.

SUMMARY

In accordance with a first aspect of the invention, there is provided an open display refrigerator comprising a refrigerated interior space, air in the refrigerated interior space being separated from air in a space exterior to the open display refrigerator by an air curtain established by a fan which blows air through an air outlet towards a corresponding air inlet which recovers air from the air curtain for recirculation to the air outlet; a first weir screen positioned proximal to the exterior space; and a second weir screen positioned distal to the exterior space, whereby a channel is formed in between the first weir screen and the second weir screen, the channel for receiving air from the air curtain before it is recovered by the air inlet.

A technical advantage of providing a second weird screen is that is reduces the impact of relatively warm air from the air curtain on items at the base of the refrigerator by capturing a relatively larger amount of air from the air curtain when compared to using a single weir screen. This can be achieved in different ways, as discussed below.

Typically, the weir screens are formed of a plastic or, in particular, an acrylic. The first and second weir screens act to create a nozzle/funnel, with the inlet to the nozzle/funnel raised with respect to the air inlet. Typically the first and second weir screen will run the entire (or most of the) width of the air inlet and are of a similar height. A technical advantage of having the first and second weir screens being a similar height is that a maximum amount of the air curtain is recovered, when compared to having weir screens of different heights.

The air inlet may comprise a grille and either, or both, of the first and second weir screens may be attached to the grille. Alternatively, either, or both, of the first and second weir screens may be attached to the body of the refrigerator, proximate the air inlet.

In some embodiments, the first and second weir screens have respective first edges that are positioned proximal to the air inlet and wherein the first and second weir screens have respective second edges that are positioned distal to the air inlet and wherein the distance between the respective first edges is larger than the distance between the respective second edges.

A technical advantage of positioning the first edges of the first and second weir screens to create a narrower opening for receiving the air curtain is that a nozzle is formed, thereby increasing the suction pressure and so more of the air curtain can be collected when compared to using a single weir screen.

In some embodiments, the first and second weir screens have respective first edges that are positioned proximal to the air inlet and wherein the first and second weir screens have respective second edges that are positioned distal to the air inlet and wherein the distance between the respective first edges is approximately equal to the distance between the respective second edges.

A technical advantage of positioning the first and second weir screens so that they are broadly parallel to each other is that the suction area is raised further up the air curtain, thereby reducing the amount of relatively warm air that is delivered to items stored on the base of the refrigerator when compared to using a single weir screen.

In some embodiments, the first and second weir screens have respective first edges that are positioned proximal to the air inlet and wherein the first and second weir screens have respective second edges that are positioned distal to the air inlet and wherein distance between the respective first edges is smaller than the distance between the respective second edges.

A technical advantage of positioning the first edges of the first and second weir screens to create a wider opening for receiving the air curtain is that more of the air curtain is captured, when compared to using a single weir screen, as there is physically a wider gap for the air curtain to enter.

In some embodiments, a portion of the air inlet is covered, such that the surface area of the air inlet for receiving air from the air curtain is reduced.

The air inlet may be covered by a separate blanking plate or, alternatively, a portion of the first or second weird screens may be shaped to cover a portion of the air inlet.

A technical advantage of reducing the surface of the air inlet is that the suction pressure is increased and therefore more of the air curtain is captured.

In some embodiments, the second weir screen is shaped such that a portion of the weir screen covers a portion of the air inlet, such that the surface area of the air inlet for receiving air from the air curtain is reduced.

In some embodiments, the first weir screen and/or the second weir screen has a rectangular cross-section.

In some embodiments, the first weir screen and/or the second weir screen has a cross-section that comprises a curve.

In some embodiments, the second weir screen extends in a vertical direction, with respect to a base of the refrigerator, for a longer distance than the first weir screen.

A technical advantage of having the second weir screen of a taller height than the first weir screen is that this reduces the spill of cold air from the interior of the refrigerator over the front of the weir screens.

In some embodiments, the first weir screen extends in a vertical direction, with respect to a base of the refrigerator, for a longer distance than the second weir screen.

A technical advantage of having the second weir screen of a shorter height than the first weir screen is that a horizontal pull of cold air across the lower shelf is created, which reduces the impact of the relatively warmer air of the air curtain on items loaded at the front of the base of the refrigerator.

In some embodiments, there is provided a kit for retrofitting the first and second weir screens as discussed above, the kit comprising: the first weir screen; the second weir screen; and an attachment for attaching the first and second weir screens to a refrigerator. The attachment can be screws, rivets, glue, a slot, a combination of these or any other method known in the art.

In some embodiments, the open display refrigerator further comprises an air curtain guide for guiding the flow of air within the air curtain. The air curtain guide may further comprise at least one light source disposed in the air curtain guide so as to illuminate the interior refrigerated storage space.

In some embodiments, the air curtain guide is in the form of an aerofoil.

An aerofoil is a type of air guide that guides air in a specific manner. An aerofoil works by being situated in the air curtain of the refrigerator, with a portion of the air curtain flowing either side of the aerofoil. The aerofoil imparts a shape into the airflow and guides the airflow in a desired direction. The specific shape of the aerofoil causes a change in the direction of flow of the air curtain as it flows over the aerofoil. A typical design of aerofoil that can be used is a cambered aerofoil. This will usually be oriented with the leading edge uppermost and the cambered surface facing away from the interior space. An aerofoil is a shape that gives rise to lower pressures on one side (on the suction surface (i.e. the cambered surface)) compared with the other side (on the pressure surface) when placed in the air curtain.

In some embodiments, the air curtain guide further comprises a front portion, wherein the front portion comprises a housing formed of a transparent plastic material for displaying at least one product label.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an open display refrigerator with a single weir screen.

FIG. 2 shows the open display refrigerator of FIG. 1 fitted with a second weir screen.

FIG. 3 shows a single weir screen attached to the base of an open display refrigerator.

FIG. 4 shows a variation of first and second weir screens attached to the base of an open display refrigerator.

FIG. 5 shows another variation of first and second weir screens attached to the base of an open display refrigerator, with the addition of a blanking plate applied to the air inlet.

FIG. 6 shows another variation of first and second weir screens attached to the base of an open display refrigerator.

FIG. 7 shows another variation of first and second weir screens attached to the base of an open display refrigerator, with the addition of a blanking plate applied to the air inlet.

FIG. 8 shows another variation of first and second weir screens attached to the base of an open display refrigerator.

FIG. 9 shows another variation of first and second weir screens attached to the base of an open display refrigerator, with the addition of a blanking plate applied to the air inlet.

DETAILED DESCRIPTION

FIG. 1 shows a cross-section through a conventional open display refrigerator 1. The refrigerator has an interior space which is maintained at a lower than ambient temperature. Within the interior space, there are four shelves and a base 9. The refrigerator 1 establishes an air curtain 3 by blowing cold air from an air outlet 2 towards an air inlet 5. A first weir screen 4 helps to prevent air from the air curtain 3 from spilling out of the front of the refrigerator. Air inlet 5 recovers air from the air curtain and at least one fan 6 within the refrigerator 1 recirculates the air to the air outlet 2 via a cooling heat exchanger 7 and a duct 8. The cooling heat exchanger is typically placed within the refrigerator 1 and maintains the recirculated air (and hence the air blown through the air outlet 2 to form the air curtain) at a desired temperature. The desired temperature is chosen to be lower than ambient and acts to prevent cold air in the interior space 2 from mixing with warm air exterior to the refrigerator 1. Items 10 to be kept cool may be stored on the base 9 of the refrigerator.

The first arrow 3 b shows the general path of the air curtain flowing from the air outlet 2 to the air inlet 5. The second arrow 3 c shows how some of the air in the air curtain spills out of the front of the refrigerator, over the front of the first weir screen 4. The third arrow 3 a shows how some air from the air curtain impinges on items 10 on the base 9 of the refrigerator. The fourth arrow 3 d shows how cold air that is expelled from perforations in the back wall of the refrigerator hits the base of the air curtain 3.

FIG. 2 shows a similar open display refrigerator 1 to that of FIG. 1, but with a second weir screen 11 attached proximate the air inlet 5. These weir screens are arranged to create a nozzle and hence increase the suction pressure where the air curtain is received in the gap between the two weir screens. The first arrow 3 b again shows the general path of the air curtain flowing from the air outlet 2 to the air inlet 5. The second arrow 3 c shows how the air that would have spilled out of the front of the refrigerator 1 without the second weir screen 11 is now retained behind the first weir screen 4 and also flows into the air inlet 5. Similarly the third arrow 3 a shows how air that would have normally impinged on items 10 stored on the base 9 of the refrigerator is now retained behind the second weir screen 11. Similarly, the fourth arrow 3 d shows how air hits the base of the air curtain 3 is now retained behind the second weir screen 11.

FIG. 3 shows a close up of the first weir screen 4 of the refrigerator shown in FIG. 1. As can be seen, air from the air curtain flows over the front of the first weir screen 4 and out of the front of the refrigerator.

FIG. 4 shows a close up of the first weir screen 4 and the second weir screen 11 a of the refrigerator shown in FIG. 1. As can be seen, air from the air curtain is retained between the two weir screens. In this embodiment, the second weir screen 11 a has a cross section that comprises a curve and the gap between the top edges of the first and second weir screens, where the air curtain is received, is smaller than the gap between the bottom edges of the first and second weir screens, proximal to the air inlet 5.

FIG. 5 shows a variation on the weir screens shown in FIG. 4. As can be seen, there is an additional blanking plate 12 that covers a portion of the air inlet 5, thereby reducing the surface area of the air inlet 5 and increasing the suction pressure. In this variation, the blanking plate 12 is separate to the second weir screen 11 a, however, it is contemplated that the second weir screen 11 a can be of a continuous construction that covers a part of the air inlet 5, thereby negating the need for a separate blanking plate 12.

FIG. 6 shows a variation of the weir screens shown in FIG. 4. In this embodiment, the second weir screen 11 b has a rectangular cross section and the first weir screen 4 is parallel to the second weir screen 11 b.

FIG. 7 shows a variation on the weir screens shown in FIG. 6. As can be seen, there is an additional blanking plate 12 that covers a portion of the air inlet 5, thereby reducing the surface area of the air inlet 5 and increasing the suction pressure. In this variation, the blanking plate 12 is separate to the second weir screen 11 b, however, it is contemplated that the second weir screen 11 b can be of a continuous construction that covers a part of the air inlet 5, thereby negating the need for a separate blanking plate 12.

FIG. 8 shows a variation on the weir screens shown in FIG. 4. In this embodiment, the second weir screen 11 c has a rectangular cross section and the gap between the top edges of the first and second weir screens, where the air curtain is received, is larger than the gap between the bottom edges of the first and second weir screens, proximal to the air inlet 5.

FIG. 9 shows a variation on the weir screens shown in FIG. 8. As can be seen, there is an additional blanking plate 12 that covers a portion of the air inlet 5, thereby reducing the surface area of the air inlet 5 and increasing the suction pressure. In this variation, the blanking plate 12 is separate to the second weir screen 11 c, however, it is contemplated that the second weir screen 11 c can be of a continuous construction that covers a part of the air inlet 5, thereby negating the need for a separate blanking plate 12.

Any of the weir screens discussed above may be provided as a kit for retrofitting an existing refrigerator. Such a kit includes a first weir screen and a second weir screen in accordance with any of the embodiments discussed above. Further, such a kit may also include a way of attaching the weir screens to a refrigerator, such as screws, nails and/or glue. 

1. A refrigerator, comprising: a refrigerated interior space, air in the refrigerated interior space being separated from air in a space exterior to the refrigerator by an air curtain established by a fan which blows air through an air outlet towards a corresponding air inlet which recovers air from the air curtain for recirculation to the air outlet; a first weir screen positioned proximal to the exterior space; and a second weir screen positioned distal to the exterior space, whereby a channel is formed in between the first weir screen and the second weir screen, the channel for receiving air from the air curtain before it is recovered by the air inlet.
 2. The refrigerator of claim 1, wherein the first and second weir screens have respective first edges that are positioned proximal to the air inlet and wherein the first and second weir screens have respective second edges that are positioned distal to the air inlet and wherein the distance between the respective first edges is larger than the distance between the respective second edges.
 3. The refrigerator of claim 1, wherein the first and second weir screens have respective first edges that are positioned proximal to the air inlet and wherein the first and second weir screens have respective second edges that are positioned distal to the air inlet and wherein the distance between the respective first edges is approximately equal to the distance between the respective second edges.
 4. The refrigerator of claim 1, wherein the first and second weir screens have respective first edges that are positioned proximal to the air inlet and wherein the first and second weir screens have respective second edges that are positioned distal to the air inlet and wherein distance between the respective first edges is smaller than the distance between the respective second edges.
 5. The refrigerator of claim 1, wherein a portion of the air inlet is covered, such that the surface area of the air inlet for receiving air from the air curtain is reduced.
 6. The refrigerator of claim 1, wherein the second weir screen is shaped such that a portion of the weir screen covers a portion of the air inlet, such that the surface area of the air inlet for receiving air from the air curtain is reduced.
 7. The refrigerator of claim 1, wherein the first weir screen and/or the second weir screen has a rectangular cross-section.
 8. The refrigerator of claim 1, wherein the second weir screen has a cross-section that comprises a curve.
 9. The refrigerator of claim 1, wherein the second weir screen extends in a vertical direction, with respect to a base of the refrigerator, for a longer distance than the first weir screen.
 10. The refrigerator of claim 1, wherein the first weir screen extends in a vertical direction, with respect to a base of the refrigerator, for a longer distance than the second weir screen.
 11. The refrigerator of claim 1, wherein the refrigerator further comprises an air curtain guide for guiding the flow of air within the air curtain.
 12. The refrigerator of claim 11, wherein the air curtain guide is in the form of an aerofoil.
 13. The refrigerator of claim 11, further comprising at least one light source disposed in the air curtain guide so as to illuminate the interior refrigerated storage space.
 14. The refrigerator of claim 11, wherein the air curtain guide further comprises a front portion, wherein the front portion comprises a housing formed of a transparent plastic material for displaying at least one product label.
 15. The refrigerator of claim 1, wherein the refrigerator is an open display refrigerator.
 16. A method, comprising: attaching a first weir screen proximal to an exterior space of a refrigerator; and attaching a second weir screen distal to the exterior space of the refrigerator such that a channel is formed in between the first weir screen and the second weir screen, the channel configured to receive air from an air curtain established by a fan which blows air through an air outlet towards a corresponding air inlet before it is recovered by the air inlet.
 17. The method of claim 16, wherein the refrigerator is an open display refrigerator. 